Magic Items

In the event that Terry survives the adventure, he bestows on the party the opportunity to make a greater fey pact, offering either a Wish or a copy of his spell book (A Tome of Clear Thought).
Breaking the Pact:
In the event that a character fails to eat ice-cream as part of their morning meal for three days in a row, these benefits are lost, in the case of the Wish it is removed from the character, in the case of the tome, the book is rendered blank, and all knowledge gained is forgotten.

Wondrous item, rare
You can use an action to blow this horn. In response, warrior spirits from the plane of Ysgard appear within 60 feet of you. These spirits use the berserker statistics. They return to Ysgard after 1 hour or when they drop to 0 hit points. Once you use the horn, it can't be used again until 7 days have passed.
The silver horn summons 2d4 + 2 berserkers.
The berserkers are friendly to you and your companions and follow your commands.

Heavy armor, uncommon
Mithral is a light, flexible metal. A mithral chain shirt or breastplate can be worn under normal clothes. If the armor normally imposes disadvantage on Dexterity (Stealth) checks or has a Strength requirement, the mithral version of the armor doesn't.
Made of interlocking metal rings, chain mail includes a layer of quilted fabric worn underneath the mail to prevent chafing and to cushion the impact of blows. The suit includes gauntlets.

Wand, uncommon
This wand has 7 charges. While holding it, you can use an action to expend 1 or more of its charges to cast the magic missile spell from it. For 1 charge, you cast the 1st-level version of the spell. You can increase the spell slot level by one for each additional charge you expend.

The wand regains 1d6 + 1 expended charges daily at dawn. If you expend the wand's last charge, roll a d20. On a 1, the wand crumbles into ashes and is destroyed.

Wondrous item, rare (requires attunement by a wizard)

This thick, scorched spellbook reeks of smoke and ozone, and sparks of energy crackles along the edges of its pages. When found, the book contains the following spells: Contingency, Fireball, Gust of Wind, Leomund's Tiny Hut, Magic Missile, Thunderwave, and Wall of Force. It functions as a spellbook for you.

While you are holding the book, you can use it as a spellcasting focus for your wizard spells.

The book has 3 charges, and it regains 1d3 expended charges daily at dawn. You can use the charges in the following ways while holding it:

If you spend 1 minute studying the book, you can expend 1 charge to replace one of your prepared wizard spells with a different spell in the book. The new spell must be of the evocation school.
When one creature you can see takes damage from an evocation spell you cast, you can use your reaction and expend 1 charge to deal an extra 2d6 force damage to the creature and knock the creature prone if it is Large or smaller.